In-Game Science
"As much as TerraGenesis strives to be an accurate representation of the science of terraforming, the true process will require the focused effort of millions of people over decades or centuries, and that would make for a terrible game. No computer program, let alone single-player game, could accurately simulate the entire experience, any more than a historical strategy game could accurately encapsulate the experience of human history. Therefore, in the name of making an enjoyable and educational gaming experience, some scientific principles were simplified or altered slightly. The largest of these are listed below: ''- The color of a planet's atmosphere is indicative of its composition. In reality, Earth's atmosphere appears blue because of Rayleigh scattering, a process largely unrelated to the amount of oxygen present therein, and other planets get their differing colors from other chemicals, such as sulfuric acid turning the clouds of Venus yellow. In order to provide players with a visual clue to the planet's atmospheric composition, gameplay renders oxygen-poor atmospheres as red, oxygen-oversaturated atmospheres as yellow, and oxygen-nominal atmospheres as blue.'' ''- Atmospheric composition has been conceptually reduced to 'oxygen' and 'not oxygen.' In reality, the makeup of each planet's atmosphere is unique, consisting of varying levels of thousands of different elements and compounds, and would pose radically different challenges to those attempting to transform each. In order to streamline the experience for players without chemistry PhDs, gameplay assumes oxygen content is the only factor in the breathability of air.'' ''- Oxygen percentage remains constant during atmospheric pressure changes. In reality, pumping carbon dioxide (CO2) or other gasses into a planet's atmosphere to warm it up and increase the pressure, or removing it to do the opposite, would alter the oxygen content of the planet significantly. To keep our players from having to play the game with a calculator in the other hand, gameplay assumes a constant oxygen percentage independent of atmospheric pressure. The one exception: if a planet's atmosphere completely disappears, its oxygen content will drop to 0.'' ''- Sea levels are based on elevation, rather than volume. In reality, increasing the sea level of a planet will depend significantly on the planet's topography: flooding a narrow canyon requires less water than flooding a broad plain, for example, and physical obstacles can block the flow of water to sub-sealevel areas. To streamline planet rendering and player understanding, sea level changes are treated as linear values of elevation above the nadir, the lowest point of elevation on a planet's surface.'' ''- The maximum biomass quantity and effects on a planet have been estimated based on gameplay requirements. In reality, our planetary biosphere is one of the most complex systems in the known universe, with wide-ranging and often unknown effects on our planet. In order to streamline the game mechanics and increase player understanding, gameplay assumes a biomass maximum of 300,000 megatonnes per planet size class (Tiny, Small, Earth-like, Large, Huge), and a consistent, predictable release of oxygen into the atmosphere based on biomass quantity.'' ''- Some numerical values have been rounded slightly for ease of understanding, such as Earth's atmospheric oxygen content being listed as 210,000 ppm rather than 209,460 ppm.'' ''- Facility effects have been estimated, due to many being based on unproven concepts proposed by physicists, engineers, and astronomers throughout the last century.'' ''- Several playable planets have been created as fictional constructs, to highlight and explore different gameplay scenarios.'' ''- Surface temperatures remain constant after manipulation. In reality, a cold planet would begin to cool down as soon as you started warming it, and a hot planet would begin warming back up as you cooled it. To avoid an exercise in frustration, TerraGenesis assumes that a planet can maintain any temperature it can reach, and as such does not include complex calculations for entropy and the diffusion and the heat over time.'' Despite these minor changes and gameplay simplifications, we believe TerraGenesis remains a largely faithful representation of the challenges, opportunities, and potential of space exploration and terraforming. We hope our players will enjoy the gameplay experience, and perhaps even be inspired to learn more about the sciences of astronomy, astrophysics, space exploration, and planetary engineering."